Buffing-pad holder.



PATENTED Nov. 1903.

T. ROBINSON.

BUFFING PAD HOLDER.

- APPLICATION TILED JAN. 10, 1903.

N0 MODEL.

UNITED STATES Patented November 3, 1903.

PATENT ()FFICE. A

BUFFlNG-PAD HOLDER.

SPECIFICATION forming part of Letters Patent No. 743,035, dated November 3, 1903. Application filed January 10, 1903. Serial No. 138,539. on) model.)

To all whom it may concern:

Be it known that I, THOMAS ROBINSON, of Bradford, county of Essex, State of Massachusetts, have invented an Improvement in Buffing-Pad Holders, of which the following description, in connection with the accompanying drawings, is a specification, like characters on the drawings representing like parts.

This invention relates to that class of buffing devices in which a circular holder is supported on the end of a rotating shaft, said holder bearing a pad on one side, over the surface of which a circularly-shaped covering having an abrasive surface is secured; said covering being provided with ears or lugs at its edge, which extend about the edge'of the holderand are secured to the side thereof opposite the pad by suitable clamping means. The clamping means for the abrasive padcover has usually been tightened by a nut threaded on the shaft or holder base. Experience has shown that unless this nut is frequently tightened the cover will become disconnected from the holder, and to either tighten the nut or readjust the cover causes loss of much time by the operator. The principal reason for the difliculty in holding the cover in place in this manner is due to the fact that the abrasive surface of the cover crumbles under the pressure of the members of the clamp as the cover is pulled and twisted in use. Moreover, the jar or vibration of the holder as it rotates often loosens the clamping-nut.

The object of my invention is to provide a form of clamp for the abrasive covering in a pad-holder of the above-described character in which the members of the clamp are automatically tightened as the holder is rotated and the work is pressed against the cover, so that as the abrasive material crumbles the cover will not become loosened.

Afurther object of my invention is to produce a form of holder and clamp which is simplified to such an extent as to materially decrease the cost of manufacture of such device.

In the accompanying drawings, Figure l is a side elevation of my improved clamp and holder. Fig. 2 is a central longitudinal crosssection thereof. Fig. 3 is an elevation of the holder, showing the clamp opened to permit the insertion of the abrasive cover. Fig. 4. is a view of the rear side of the pad member, and Fig. 5 is a View of the concave side of the annular clamping member.

The shaft a is journaled in one or more bearings 12 and is driven to the right by a pulley c, as indicated by the arrow in Fig. 2. Said shaft is provided with an extension 61 at one end thereof of less diameter than the main part of the shaft, thereby providing a shoulder a thereon. Said extension is provided with a left-hand screw-thread d, said thread being cut in the opposite direction from that in which the shaft is driven by pulley c.

The pad or cushionf is of circular convex form and is preferably glued to a leather back f, which is in turn secured by screws to one side of a circular metal base 9, the other or outer side thereof having aface which is fiat and smooth and constitutes the face of one member of a clamp, as hereinafter explained. Said base 9 is provided with an integral centrally-arranged projecting boss g, which is internally screw-threaded to receive the screw-threads d, of the extension cl.

A clamping-ring h of conical-convex form is arranged to slide on said boss g, and said ring is provided with a boss 72. on its convex side, the end of which is adapted to rest against the shoulder a. on the shaft. The diameter of said ring his substantially the same as that of base 9, and its rim portion is provided with a clampingface adapted to bear against the face of the base g near the outer edge thereof, said ring thereby constituting the other member of the clamp. A spring 41 encircles the boss g of the base, and one end thereof-engages said base and the other end engages the concave side of the clampingring h.

A well-known form of abrasive cover 2" is illustrated in the drawings, said cover'being circular in form and having ears j thereon. To secure said cover in position, the base g is unscrewed from the shaft a short distance, so that the ring h is moved from the base g by spring 2', as illustrated in Fig. 3, and then the cover is stretched over the face of the pad f and said ears are tucked between the faces of the clamping members 9 and 71. The operator while holding the pad in place and the head stationary with one hand will then screw the extension d of the shaft into the boss g of the base, so that the shoulder a on said shaft will press the ring it against the ears of the cover and securely clamp the same in place. As the holder is rotated the work is pressed against the cover, and this action tends to retard the rotation of the head, so that there is a constant tendency to screw the shaft farther into the boss, and thus draw the two clamping members more closely together, with the result that as the abrasive material crumbles and the ears of the cover become reduced in thickness the clamping members will be correspondingly tightened. The corrugation of the faces of the clamping members is unnecessary and undesirable.

It will be observed that the distance from the face of the base 9 to the shoulder a at the end of the shaft is short and that the adjacent end of bearing b may extend to said shoulder. For this reason the holder is held from vibration by thebearing and may be rotated at as high a speed as is desirable.

The operator may readily remove the cover" by holding the head with one hand and rotating the shaft backward with the other, the size of the holder making the use of a Wrench unnecessary.

The above-described construction is simple and may be easily constructed, as it comprises but few parts.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

In a buffing device of the character described, the combination with a pad having an abrasive covering, means for securing said covering to the pad comprising two clamping members, one of them being disk-shaped and bearing the pad on one side and having a clamping-face on the other side, the other member being of annular form and having a clamping-face on one side, a shaft having one end passing through said annular member and having a screw-thread connection with said pad member, a shoulder on said shaft for engaging the opposite side of said annular member from its clamping-face, the length of said screw-threaded connection permitting the opposite sides of said ring to simultaneously engage the clamping-face of the pad member and said shoulder respectively, whereby said clamping-faces may be forced together automatically by the rotation of the shaft as the abrasive material disintegrates between said faces,substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

THOMAS ROBINSON.

Witnesses:

LoUIs H. HARRIMAN, H. B. DAVIS. 

